Leuco diethylgallocyanin.



WILHIELM LOMMEL,

OF ELBERFELD, GERMANY, ASSIGNOR TO PATENT OFFICE.

FABBENFABRIKEN GERMANY, A. CORPORATION 013 Patented June 28, 1910.

VORCLVI. FRIEDR. BAYER 86 C0,, OF ELBERFELD, GERTJIANY.

LEUCO DIETHYLGALLOCYANIN.

962,712, Specification of Letters Patent.

No Drawing.

T 0 all whom it may concern: 1

Be it known that I, im-innit LOMMEL, l doctor of philosophy, chemist, citizen of the German Empire, residing at Elberfeld, Germany, have invented new and useful Improvements in Leuco Diethylgallocyanins, of which the following is a specification.

In the United States Letters Patent No. 629666 leuco derivatives of gallocyanins are described.

The gallooyanin derived from nitrosodiethylanilin and gallic acid has hitherto not been particularly described and my experience is that by the processes hitherto known for the production of these compounds it cannot be obtained in technical yields.

1 have found a process for producing this dye with a good yield, which process consists in using for the condensation salts of the nitroso compound of diethylanilin with such acids as form with the nitroso compound difficultly soluble salts.

My present invention relates to the production of the leuco diethylgallocyanin by treating the diethylgallocyanin (obtained from nitrosodiethylanilin and gallic acid) with reducing agents or executing the reduction by electrolytical methods.

In order to illustrate the new process more fully the following example is given, the 1 parts being by weight :36 parts of diethylgallocyanin hydrochlorid are stirred together with water and 30 parts of hydrochloric acid 19 B. and 9 parts of Zinc l Application filed. March 4, 1910.

Serial No. M7313.

dust are slowly added. The reaction is complete after the mixture has been stirred for some time on gently heating. The new leuco compound separates from the filtrate aftersome time. It can be used as paste or it is filtered off, washed and dried. It is in the shape of its hydrochlorid a greenish powder soluble in concentrated sulfuric acid with a reddish-gray coloration. It is soluble in water with a greenish-yellow color. free base is separated from its aqueous solution by the addition of sodium acetate. The free base soon turns blue in consequence of oxidation.

I claim The herein described new leuco compound of diethylgallocyanin, which is in the shape of its hydrochlorid a greenish powder soluble in water with a greenish-yellow color, dissolving in concentrated sulfuric acid with a reddish-gray color; the free base being separated by the addition of sodium acetate to the aqueous solution of the hydrochlorid, the free base soon turning blue in consequence of oxidation, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

WILHELM LOMMEL. 1,. s]

WVitnesses OTTO Koivio, CHAS. J WRIGHT. 

